Return Spring Guillotine Slide Firewall

How to keep the Cessna 170 flying and airworthy.

Moderators: GAHorn, Karl Towle, Bruce Fenstermacher

Post Reply
User avatar
MoonlightVFR
Posts: 624
Joined: Sun Jan 02, 2005 5:55 pm

Return Spring Guillotine Slide Firewall

Post by MoonlightVFR »

IPC page 95/95A - Fig 55-23 P.N. 0713019-37

I need a new one. Where can I purchase an exact replacement?

Thinking that this finely engineered Air valve required a certain amount of Spring Tension to support the Push-Pull
design concept. Guillotine Slide door in Firewall.

Going down to the local ACE AVIATION STORE could result in too much or too little spring tension.

Hoping that some one before me has solved this small technical issue and will share to the forum.
gradyb, '54 B N2890C
User avatar
Bruce Fenstermacher
Posts: 10313
Joined: Tue Apr 23, 2002 11:24 am

Re: Return Spring Guillotine Slide Firewall

Post by Bruce Fenstermacher »

While your at ACE keep in mind the sprng is available from several Cessna parts suppliers for about $68.
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
User avatar
MoonlightVFR
Posts: 624
Joined: Sun Jan 02, 2005 5:55 pm

Re: Return Spring Guillotine Slide Firewall

Post by MoonlightVFR »

If some one could measure the length of the Spring and the approximate diameter that would be a great help to me.

Regards
gradyb, '54 B N2890C
User avatar
MoonlightVFR
Posts: 624
Joined: Sun Jan 02, 2005 5:55 pm

Re: Return Spring Guillotine Slide Firewall

Post by MoonlightVFR »

Bruce

Can you share dealer name w me. Part 0713019-37 IPC pg 95 fig 55-23
Yingling Aviation no help - referred to Textron . Very complex to establish an account.

If I just had the length of stock spring and the O D of spring I could do this.

There is a balance between friction of cable inside Bowden sheaf and the Spring tension required for smooth operation.
gradyb, '54 B N2890C
User avatar
Bruce Fenstermacher
Posts: 10313
Joined: Tue Apr 23, 2002 11:24 am

Re: Return Spring Guillotine Slide Firewall

Post by Bruce Fenstermacher »

Here are a few. Google Cessna 0713019-37 and you ill get the same list.

Cessna Part No. 0713019-37 Spring - General Inventory - Air Power, Inc.
http://www.airpowerinc.com/productcart/ ... subcat=108...
Cessna Part No. 0713019-37 Spring,SPRING 1235,General Inventory,Air Power, Inc.
Cessna 172 Cabin Heat Valve PN 0713019 | eBay
https://www.ebay.com › ... › Parts & Accessories › Aviation Parts & Accessories › Parts
Find great deals for Cessna 172 Cabin Heat Valve PN 0713019. ... 0713019-37 -Cessna 175 A 172 cabin heat flap valve arm & spring 0513109-6 0713019-37.
SPRING 0713019-37 - CessnaDirect.com
cessnadirect.com/0713019-37
SPRING 0713019-37. ... 0713019-37 SPRING. SKU: 0713019-37. $62.14. Regular Price: $76.71 | YOU SAVE 19.0%. *Prices and availability subject to change ...
0713019-37 - CessnaParts.com
https://www.cessnaparts.com › Uncategorized › 0713019-37
0713019-37 SPRING. ... SKU: 0713019-37 Category: Uncategorized ... Email us your hi-res photo and it may be added to the header of Cessnaparts.com
Airframe - Airframe-General - Texas Air Salvage
https://www.texasairsalvage.com/Airfram ... rframe...3
Show Details. Category: Airframe > Airframe-General From a: 1982 Cessna 172RG ... PN: 0713019-37, ItemID: 66743. Cessna - Spring-Cabin Air Valve
Airframe Parts - Texas Air Salvage
https://www.texasairsalvage.com/Airfram ... ...goto=23
PN: 0713019-37, ItemID: 66743. Cessna - Spring-Cabin Air Valve · Show Details. Category: Airframe > Airframe-General From a: 1958 Cessna 172 ...
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
User avatar
Bruce Fenstermacher
Posts: 10313
Joined: Tue Apr 23, 2002 11:24 am

Re: Return Spring Guillotine Slide Firewall

Post by Bruce Fenstermacher »

Just in case you want a picture of the spring which you could use to gauge the length base on it's size in relation to the flap. You can see the gauge wire used and count the coils if you want.
s-l1600.jpg
Looks like about a 3" piece of screen door spring or something similar. I could try a lot of springs before "springing" $70 for one. And if you modify what ever spring works that you find, it's an owner produced part.
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
User avatar
GAHorn
Posts: 20967
Joined: Fri Apr 12, 2002 8:45 pm

Re: Return Spring Guillotine Slide Firewall

Post by GAHorn »

It hasn't nearly the tension of a screen-door spring. It's only function is to allow the door to slide open in the event the friction of the Bowden-cable is relaxed from the cockpit. Think about this. It does NOT provide a strong opening-force because THE FUNCTION OF THE VALVE IS TO ISOLATE THE COCKPIT FROM ENGINE COMPARTMENT in the event of fire/smoke/fumes. Once activated it is unlikely that the door should be re-opened during flight.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
User avatar
n2582d
Posts: 2808
Joined: Mon Apr 29, 2002 4:58 am

Re: Return Spring Guillotine Slide Firewall

Post by n2582d »

MoonlightVFR wrote:If some one could measure the length of the Spring and the approximate diameter that would be a great help to me.

Regards
p/n 0713019-37 Click to enlarge
p/n 0713019-37 Click to enlarge
1613094D-1A5E-498B-8AE4-9378D218F17A.jpeg
I found a spring similar to p/n 0713019-37 at my local True Value dealer. The packaging says the wire diameter is 0.031”. I measured it slightly larger at 0.0345”. It is noticeablely stiffer than 0713019-37. I’m still hunting for a new replacement at a reasonable price.

Looking at Century Spring’s website it looks like their p/n 80280 or 80280S might work although they have a smaller diameter at 0.240”.
Gary
User avatar
Bruce Fenstermacher
Posts: 10313
Joined: Tue Apr 23, 2002 11:24 am

Re: Return Spring Guillotine Slide Firewall

Post by Bruce Fenstermacher »

Gary, since the pull is the critical point here, you might experiment a bit with a fish scale and see what you think the range of pull might be. Hillman Hardware has a spring item 851626 that is 1/4" diameter x 5-7/8" with a pull of 2.734 lb. This spring might be shortened and be perfect for the application. Another detail not given with your measurement is how many coils in the spring or in an inch. Though with some math 4.6"/.025 is 184 coils or 40 per inch. A spring of about 40 coils an inch and just over 1/4 dia. would have about the same pull.

https://www.hillmangroup.com/us/en/Home ... 1626#specs

A spread sheet of all Hillman tension springs sorted by diameter.
Hillman Tension Springs.xls
(45.5 KiB) Downloaded 681 times
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
User avatar
daedaluscan
Posts: 497
Joined: Fri Apr 20, 2012 7:03 pm

Re: Return Spring Guillotine Slide Firewall

Post by daedaluscan »

I would be more interested in the spring tension than it’s matching dimensions.
Charlie

1956 170B C-GDRG #27019
User avatar
GAHorn
Posts: 20967
Joined: Fri Apr 12, 2002 8:45 pm

Re: Return Spring Guillotine Slide Firewall

Post by GAHorn »

Let me reemphasize that the function of the Bowden cable is to SHUT the valve. The only function of the spring is to assist the guillotine-valve to re-open when the Bowden cable is pushed back "in" at the cockpit to assist the valve to slide back open. One does not want a spring which is so strong as to over-ride the pilots desire to close that valve. It is very unlikely to be necessary to re-open that valve in-flight if it is used for its intended purpose (fire/smoke/etc.) The valve can be easily returned to the open position after landing manually inside the cowling, even without a spring.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
Post Reply